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nginx 负载均衡简单实现
nginx能够实现负载均衡，在被反向代理的服务器中进行按需的负载均衡配置：
下面是一个配置文件：
#user nobody;
worker_processes 1;
#error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;
#pid logs/nginx.pid;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
#log_format main '$remote_addr - $remote_user [$time_local] "$request" '
# '$status $body_bytes_sent "$http_referer" '
# '"$http_user_agent" "$http_x_forwarded_for"';
#access_log logs/access.log main;
sendfile on;
#tcp_nopush on;
#keepalive_timeout 0;
keepalive_timeout 65;
#gzip on;
upstream backend {
#ip_hash;
server 192.168.1.120:8989 weight=5;
server 192.168.1.120:8080 weight=10;
}
server {
listen 9922;
server_name firstProxyServer;
#charset koi8-r;
#access_log logs/host.access.log main;
#location / {
#root html;
#index index.html index.htm;
#}
location /ngtt{
proxy_pass http://backend/ngtt;
}
location /testnnnn{
proxy_pass http://localhost:8080/testnnnn;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
# proxy the PHP scripts to Apache listening on 127.0.0.1:80
#
#location ~ \.php$ {
# proxy_pass http://127.0.0.1;
#}
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
#location ~ \.php$ {
# root html;
# fastcgi_pass 127.0.0.1:9000;
# fastcgi_index index.php;
# fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
# include fastcgi_params;
#}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
# deny all;
#}
}
server {
listen 9977;
server_name secondProxyServer;
#charset koi8-r;
#access_log logs/host.access.log main;
#location / {
#root html;
#index index.html index.htm;
#}
location / {
proxy_pass http://localhost:8080;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
# proxy the PHP scripts to Apache listening on 127.0.0.1:80
#
#location ~ \.php$ {
# proxy_pass http://127.0.0.1;
#}
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
#location ~ \.php$ {
# root html;
# fastcgi_pass 127.0.0.1:9000;
# fastcgi_index index.php;
# fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
# include fastcgi_params;
#}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
# deny all;
#}
}
# another virtual host using mix of IP-, name-, and port-based configuration
#
#server {
# listen 8000;
# listen somename:8080;
# server_name somename alias another.alias;
# location / {
# root html;
# index index.html index.htm;
# }
#}
# HTTPS server
#
#server {
# listen 443 ssl;
# server_name localhost;
# ssl_certificate cert.pem;
# ssl_certificate_key cert.key;
# ssl_session_cache shared:SSL:1m;
# ssl_session_timeout 5m;
# ssl_ciphers HIGH:!aNULL:!MD5;
# ssl_prefer_server_ciphers on;
# location / {
# root html;
# index index.html index.htm;
# }
#}
}
upstream backend {
#ip_hash;
server 192.168.1.120:8989 weight=5;
server 192.168.1.120:8080 weight=10;
}
server {
listen 9922;
server_name firstProxyServer;
#charset koi8-r;
#access_log logs/host.access.log main;
#location / {
#root html;
#index index.html index.htm;
#}
location /ngtt{
proxy_pass http://backend/ngtt;
}
location /testnnnn{
proxy_pass http://localhost:8080/testnnnn;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
# proxy the PHP scripts to Apache listening on 127.0.0.1:80
#
#location ~ \.php$ {
# proxy_pass http://127.0.0.1;
#}
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
#location ~ \.php$ {
# root html;
# fastcgi_pass 127.0.0.1:9000;
# fastcgi_index index.php;
# fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
# include fastcgi_params;
#}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
# deny all;
#}
}其中权重weight越大，优先级越高。
进行测试的时候是这样，通过对一个服务器进行关闭，然后查看访问时宕机的次数。比如现在两台服务器都开启，现在关闭其中的一台——192.168.1.120:8989，然后再次进行访问，访问完成后，发现没3次会有一次出现宕机的现象。
如果发现了宕机，那么管理员此时可以直接这样配置：
upstream backend {
#ip_hash;
server 192.168.1.120:8989 down;
server 192.168.1.120:8080 weight=10;
}然后，输入nginx命令:
nginx -s reload即可恢复正常的访问。
此时全力恢复192.168.1.120:8989，恢复成功后，把nginx的配置文件更改回来，再次重新启动（nginx -s reload）即可。